Transmission control system



July 13, 1948. J. a. POLOMSKI TRANSMISSION CONTROL SYSTEII 4 Sheets-Sheet 1 Filed Sept. 15, 1942 mws J. B. POLOMSKI TRANSIISSIOH CONTROL SYSTEM July 13, 1948.

4 Sheets-Sheet 2 Filed Sept. 15, 1942 V0 cuwn Half 39 4 Sheets-Sheet 3 Governor J. B. POLOMSKI TRANSMISSION CONTROL SYSTEM J'o/ena/d 36 July 13, 1948.

Filed Sept. 15, 1942 i i n 161v COIL .D/ls/r/Zu/ar 0 Ja/eno/a' IGM can.

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IRARSIISSIOH CONTROL SYSTEI Filed Sept. 15, 1942 4 Sheets-Sheet 4 fnvenzr: \fo'lin .5. Polanski Patented July 13, 1948 TRANSMISSION CONTROL SYSTEM John B. Polomski, Detroit, Mich, assignor to Borgporation of Illinois Warner Co poration, Chicago, 111., a cor- Applioation September 15, 1942, Serial No. 458,479

1': Claims. 1

This invention relates to a variable speed ratio power transmitting device of the automatic type such as may be used with automotive vehicles and particularly to a control system therei'or. 1 There has been devised a four-speed automatic transmission having two Maybach type Jaw clutches for controlling the shifts to the various speed ratios. This transmission incorporates an electrical control system for operating the two clutches in such a manner that the transmission normally starts in the lowest speed and then above a predetermined speed which is rather low both clutches are simultaneously actuated to make possible a shift into the highest speed. To provide a performance ratio however, it is possible to downshift under manual control to the third or next highest speed ratio. It has been found however that under certain circumstances it will be desirable to effect a second downshift to the second speed ratio, particularly (in the case of passenger automobiles) when the vehicle is moving between 15 and 25 miles per hour.

The principal object of this invention is to provide a means, in a transmission of the type described, for effecting a second downshift to provide increased performance for the vehicle in which the transmission is installed.

A more specific object of this invention is to provide an electrical control system for electromagnetic means controlling the operation of a pair or clutches wherein both clutches are operated. by and under control of a governor switch upon increasing speed of the vehicle, and both clutches are individually operable under-manual control for effecting downshifts in the transmis. sion.

A still more specific object is to provide suitable switches, relays and other controls connected together in a manner to produce the desired result.

These and other objects and features of this invention will become apparent from the following detailed description and the accompanying drawings in which:

Fig. 1 is a schematic diagram of a transmission to which this invention is particularly well adapted. including cross-sections through the principal electrical controls therefor;

Fig. 2 is a wiring diagram showing how the controls are connected with the throttle-operated switch and with one another. In this figure the circuit is shown with current shut oil and the vehicle standing still:

Fig. 3 is similar to the wiring diagram of Fig. 2, showing the condition oi the various elements 2 thereof when the ignition switch is turned on and the vehicle is moving less than 15 M. P. H.:

Fig. 4 shows the condition of the circuit when the vehicle is moving between 15 and 25 M. P. H. and the operator desires greater performance;

Fig. 5 shows the condition of the circuit when the vehicle is moving above 25 M. P. H. and the operator desires greater performance; and

Fig. 6 shows the condition of the circuit when the vehicle is moving between 15 and 25 M. P. H. and the engine throttle is partially opened.

Referring now to Fig. 1 for a description of the transmission itself, the engine or power shaft i6 is shown connected to a hydrodynamic coupling II which functions as an automatic clutch and vibration absorber. Coupling ii is in turn connected to a transmission input shaft l2 which transmits the power from the coupling to an input gear I: in the transmission proper. Said gear I! is in constant mesh with a gear ll mounted on a countershaft i5 and drivably associated with the countershai't through a one-way clutch I6. Said clutch i6 is so arranged as to transmit torque from gear it to countershaft it and to break the connection so as to transmit no torque when countershaft ii is the driver. On countershaft i5 is mounted a gear ll of intermediate size which is in constant mesh with a gear ll loosely mounted on output shaft i! so as to be freely rotatable thereon. A smaller gear 20 is loosely mounted on countershaft i5 and is provided with a clutch 2| by which it may be made to rotate with countershaft iii. In mesh with gear 20 is a gear 22 which is adapted to drive output shaft i9 through a one-way clutch 22 when gear 22 is the driver.

A fourth gear 24 is mounted for rotation with countershaft iii and is adapted to be meshed with an idler gear 25 slidabiy mounted on a second countershaft 2t. Said idler gear 25 in turn is meshable with a gear 21 rotatable with driven shaft i8.

Gear ill may be connected to gear l3 and to output shaft is by means of jaw clutches 28 and 29 respectively. Jaw clutch 28 is provided with a siidable toothed clutch element 30 having a. groove 3i adapted to be contacted by the end 32 of a lever 38 the operation of which is controlled eiectromagnetlcally. Similarly, clutch 28 is provided with a toothed movable element 34 having an annular groove 38 in which is seated a yoke 26 having an arm 31 the movement of which is con trolled by an electromagnet 38. The law clutches 28 and 29 are oi. the Maybach type, and the ends of the teeth of the engaging elements of each clutch are beveled, such that when the elements rotate in one direction relative to each other, the beveled tooth ends maintain the elements out of mesh, but when the relative rotation between the elements is reversed and the elements are substantially synchronised in speed. then the beveled tooth ends facilitate engagement of the elements.

The ratios obtainable through the transmission are as follows: I

Neutral is obtained by releasing all of the clutches and sliding idler gear 28 to the position shown in Fig. 1.

Low speed is obtained by engaging clutch II and leaving clutches II and 29 disengaged, Idler ii is left in the right hand position for all forward speeds. The gear train is then from shaft l2 and input gear II to gear ll, one-way clutch it, countershaft ll, gear i1, clutch 2|, gears 2| and 22, overrunning clutch If and output shaft ll.

For second speed. clutch II remains enga ed and clutch a is also engaged. The gear train is then from input gear I: to gear ll, overrlmning clutch ll, conntershaft ll, gear ll, gear ll, clutch II and output shaft ll. Although clutch II is engaged, driven shaft Is is rotated faster than ear 22, and the overrunning clutch 2! will break the connection therebetween.

For third speed, clutch 2| remains engaged, clutch 2| is engaged, and clutch 2! is disengaged. The gear train is then from shaft l2 and gear II through clutch II to gear II, thence through gear ll on countershaft II, clutch 2|, gear 20, gear 22, overrunning clutch 23 to output shaft I.

For fourth or direct speed both clutches II and 2! are engaged and the drive is then from gear II through clutch 2!, gear I. and clutch 2! to driven shaft ll.

Reverse is obtained by releasing all clutches, and sliding gear to the left as shown in Fig. l sosstoengagebothgearsil sndtl. Thedrive is then from gear I! to gear ll, overrunning clutch Ii, countershaft l8, gear 24, gear I! and gear 21 to output shaft l8.

In order to coast-against the engine in second a lock-out clutch I. is provided which looks out free-wheeling clutch II on countershaft ll. Other refinements may be employed in the transmission, but since they are not material to the irglention they will not be described here in det Secured to driven shaft is so as to be rotatable therewith is a gear II which drives a second gear 42 mounted on a shaft 43 which in turn drives a two-stage electric governor ll of any suitable character. It is understood that although gear II is shown mounted on driven shaft ll, it might be mounted on any member of the on or vehicle the rotation of which bears a fixed relation to the movement oi the vehicle.

The electric control device 39 for lever II is comprised of an elet I having an operating coil It and an armature ll influenced thereby which is connected to a pair of valves 48 and is controlling the pressure within a chamber ll associated with the device. One wall of chamber II is formed by a diaphragm II which issecuredtoarodll adaptedtostrikelever i3 and move it to the left as shown in Fig. 1 under the influence of a spring SI. With the valves 48 and I! in the pofltion shown in Fig. l, chamber I is to atmospheric pressure. the armature 41 being pulled up by energization of the coil 46. When the coil is deenergised. valves l8 and II are operated to close the chamber ll to atmospheric pressure and to expose it to a sohrce of vacuum, such as a conduit ll connected with the intake manifold 01' an internal combustion engine (not shown) driving the shaft ll. Under the latter condition, rod n will be withdrawn to the right.

A spring I! having one end anchored to a fixed point on the transmission causes lever SI to follow rod 82 when the latter is withdrawn. A switch 58 is successively closed and then opened by the movement of rod 52. Said switch It controls the ignition circuit.

A fixedly mounted switch 51 having a single pair of contacts is adapted to be closed by a bar 59 is operated by lever 13 to close the contacts when clutch 28 is engaged. A spring ill normally maintains the contacts open. The function of this switch will be described with reference to the detailed description of the circuits.

Electric control 38 is comprised of a solenoid ll, a holding coil 62, an armature I, and an 01 crating rod I all coaxially arranged in a housing ti. Rod 4 is directly connected to arm 31 ct yoke It so as to cause the latter to move with rod 64. Armature 63 engages a head I on rod 64 by means of a spring 01. An abutment 60 is provided near the opposite end of solenoid I, the abutment being secured to rod N and constantly biased to the left as shown in Fig. l by a spring 6!. When solenoid BI is energized along with holding coil 82, armature I3 is moved to the right as shown in Fig. 1 thereby compressing spring 81 against head 86 to pull rod 04 to the right and thereby disengage clutch 29. In so doing spring 69 is compressed so that as soon as solenoid II and holding coil 62 are deenergized, spring is will causea reverse movement of rod 84 which will result in the engagement of clutch 2!.

Two switches II and H are provided to control the operation of the electric device and the i nition circuit. Switch II is normally open when the solenoid 6i and holding coil 62 are deenergized whereas switch H is closed. Switch Ii controls a circuit to the solenoid ll such that as soon as armature 63 is pulled up, the circuit through the solenoid will be broken. Switch ll controls the ignition circuit and is comprised of the head 86 which is insulated from rod 64, a contact l'l movable with armature 63 and a contact OI ilxed to housing 85. Switch 10 is open when the solenoid is deenergized and when clutch is is fully engaged. It is closed when clutch is is engaged as soon as armature 63 is pulled up by energisation of solenoid 6!. Under these conditions head 66 engages contact 9| while contact 91, although normally held away from head 66 by spring ll, likewise engages head 66, the latter remaining stationary because of the torque load on clutch 2!. Switch III is therefore closed and the ignition is temporarily interrupted. This removes the torque load on clutch 28 and spring 81 then pulls rod 64 to the right to disengage the clutch. with the movement of rod 84, head It disengages contest 9! and the ignition is restored.

To facilitate the description or the circuits, electric control device 38 will be referred to hereinafter as the solenoid and the electric device ll will be referred to as the vacuum unit.

Referring now to Fig. 2 for a description of the circuits, it will be observed that governor 44 is comprised of a low speed pair of contacts I! and II, the latter contact ll being movable in accordance with the speed or the vehicle, a second pair of contacts I4 and II the latter contact II being again movable in accordance with the speed or the vehicle, and a third pair oi contacts which includes the movable contact 15 and a fixed contact 16. Contact 13 is so arranged as to remain in engagement with contact 12 until the vehicle reaches a speed or approximately 15 M. P. 1-1., and contact 15 is so adjusted as to remain in engagement with contact H until a speed of approximately 25 M. P. H. is reached, whereupon it will snap upward and engage contact it.

A throttle switch 11 is provided which is operated by the accelerator'pedal lia through a rod II on which are mounted bars 19, 80 and Bi. Four sets 01' contacts are adapted to be operated by the bars, the contacts being shown at 82, 83. B4 and 85. In addition to throttle switch II, a vacuum unit relay 85 having a single pair of contacts 81, a solenoid relay 28 having a single pair of contacts 89 and a control relay 90 having two pairs or contacts BI and 22 are also provided. Relay 82 controls the energization of relays 86 and 88, under certain conditions.

The circuit also includes an ignition switch 93, a battery 94, a distributor 95 and an ignition coil 96.

The various circuits will now be described in the principal operating conditions for the vehicle.

Ignition turned 017' and vehicle standing still.- This condition is shown in Fig. 2 and it will be observed that all of the relay contacts are broken, switch is open. switch H of the solenoid Si is made and the two lowermost pairs of contacts in the governor are likewise made. Neither the solenoid nor the vacuum unit however is energized and accordingly clutch 29 may be engaged so that the engine of the vehicle may be started by towing or pushing the vehicle, the lock-out clutch I being manually engaged for this purpose.

Ignition on, vehicle movino from 0 to M. P. H.--'I'his condition is shown in Fig. 3 and it will be observed that all three relays 86, 8B and are energized as well as holding coil 82 of the solenoid and the coil of the vacuum unit. This means that both clutches 28 and 29 are disengaged and the vehicle, ii it is moving, is in low speed. Under these conditions the operation oi throttle switch TI so as to complete the circuits across contacts 83. 84 and 85 has no eii'ect upon either the solenoid or the vacuum unit.

Ignition on, vehicle moving between 15 and M. P. H.This condition is shown in Fig. 6, and it will be observed that all of the relay contacts are broken. switch 10 is open, switch Ii is made, and the contact I! is out of contact with the contact 12 of the governor. The contact IS, in moving out of contact with the contact 12, disconnects the ground connection provided by the governor as shown in Fig. 3, and the relays and the vacuum unit operating coil and solenoid are thereby deenergized. On such deenergization oi the vacuum unit operating coil and solenoid, the spring 55 is eil'ective to move the clutch element lii into contact with teeth on the gear i8 forming part of the clutch '28, and the spring 22 is eilective to move the clutch element 34 into contact with teeth on the gear i8 forming part of the clutch 29. The clutches 28 and 29 are thereby conditioned for engagement. When the accelerator 'lld is thereafter released to allow the accelerator to move to its minimum power setting, then the elements or the clutches 2B and 29 synchronize, and the clutches 22 and 22 engage. The direct drive power train is thus completed, and the shaft i0 is driven at the same speed as the shait i2. Although the direct drive power train is ordinarily completed in the 15 to 25 M. P. H. speed range, it is apparent that the power train may similarly be completed above 25 M. P. H.. since the contact II remains out of contact with contact 12, and the circuit including contacts ii and II. which are brought together at 26 M. P. H.. is broken at switch 51 and at contacts 28.

Ignition on, vehicle moving between 15 and 25 M. P. H. and throttle switch 77 in downshi/ting position.This condition is shown in Fig. 4. When the shiit was made into direct drive. switch 81 was operated by arm II to close its contacts and complete the circuit from contact ll of governor 44 to one or the contacts ll of throttle switch 11. Thus with the throttle switch in the downshii'ting position a circuit is completed from the battery through relay 8B, governor contacts ll and I6, switch I51 and contacts 82 of the throttle switch TI to ground. This closes contacts ll oi relay 88 and energizes the operating coil I! of the vacuum unit, which controls the shift oi the clutch 28. It will be recalled that when the vacuum unit operating coil 48 is energized. rod 52 will move outward under the influence of spring 83 to disengage clutch 28. This is facilitated by switch it operated by rod 52 which momentarily completes a circuit from the ignition coil and distributor through contacts 84 of the throttle switch to ground, thus interrupting the ignition to relieve the teeth of clutch 28 of torque. Sprin 53 of the vacuum unit then snaps the movable element Ill oi clutch 28 to disengaged position. When this occurs switch I! will of course be operated to break the circuit therethrough and the vacuum unit operating coil will again be deenergized, thereby creating the conditions for reengaging clutch 22 as soon as the operator releases the accelerator pedal sumciently long to synchronize the elements 01 clutch 28. The downshifting position oi throttle switch ll corresponds to the kickdown position or maximum power setting of the accelerator pedal Ila. It will be observed that under the conditions described above the operation of the throttle switch has no eilect whatsoever upon the solenoid for operating clutch.

Vehicle moving above 25 M. P. H. in direct drive, throttle switch in downshifting position-This condition is shown in Fig. 5. As before switch 51 is again operated to close the contacts therethrough and thus complete a. circuit from contact II 01' the governor through contacts I3 of throttle switch 11 to ground. Since contact 15 at speeds above 25 M. P. H. breaks the circuit through contact 14 which controls relay 8! and makes the circuit through contact 18 which controls relay 88, the latter will be operated and will energize the solenoid. The solenoid is shown in Fig. 5 in the condition obtaining after operating coil 6i has ceased to function by virtue oi the breaking 01' contact ii, and holding coil 82 is functioning to maintain armature 61 in its pulled up position. Since contacts 85 of the throttle switch are made. the temporary closing of the switch 10 by the movement of armature 63 against head 88 as described above will ground the isnition and thereby relieve clutch 22 of torque temporarily. When the movable element 34 of clutch 29 is withdrawn following the removal of torque therefrom. both sets oi contacts Iii and Ii are or course opened and the transmission will be conditioned for third speed operation as long as the throttle switch 11 is maintained in its depressed position. It will be observed that no do to second speed is possible above 25 H. K. due to the transfer of governor contact II from contact 14 to contact ll.

'lhe contacts I! of throttle switch I! are used merely to remove the torque load on both clutches when the vehicle is coasting to a stop and the normal idling speed of the engi e is such that it tends to drive the output shaft at a speed in excess of the speed at which the contacts 12 and II are adapted to close. These contacts If also serve to remove such torque load when the vehicle is driving uphill in direct drive and its sp ed drops below iliteen miles per hour. The hy-' draulic coupling produces a constant drag even at idling speeds of the engine and accordingly the teeth of both clutches would be constantly loaded once they. were engaged and could not be disengaged automatically under the influence oi the power devices provided. Contacts II are therefore arranged to be operated at the released position of the accelerator pedal, when the output shaft has slowed down below the speed at which contacts II and 18 close to condition the control system to disconnect both clutches fl and II. When the vehicle is moving uphill in direct drive below fifteen miles per hour. momentary release of the accelerator pedal will complete a circuit to ground through closed switch It by connecting the contacts II. Torque on clutches I. and II is thereby relieved so that they may be disengaged. If the vehicle is merely coasting to a stop on level ground with the accelerator released, the vehicle brake may be employed to cause the vehicle to move less than fifteen miles per hour for conditioning clutches It and 28 for disengagement, whereupon the ignition will be interrupted by the circuit to ground through switch II and contacts 82. In the form shown contacts I! are connected by switch bar II which also serves in kickdown position to connect contacts ll.

Numerous other refinements and interlocks may be provided for the transmission as desired without departing from the spirit of the invention. It should be understood therefore that the scope of this invention is not intended to be limited to the above illustrative description but is to be determined by the appended claims.

I claim:

1. A variable speed ratio power transmitting device comprising input and output members, a plurality of gear trains for driving the output member from the input member. at least two coupling means for establishing said gear trains, and means for controlling the operation of the coupling means. said control means including an accelerator for controlling the power impressed on said input member, means under the control of said accelerator for simultaneously effecting an operation of the coupling means in one sense when said accelerator is moved to its minimum power setting and means under the control of said accelerator for individually effecting an operation or the coupling means in the opposite sense when said accelerator is moved to its maximum power setting.

2. A variable speed ratio power transmitting device comprising input and output members, a plurality of gear trains for driving the output member from the input member. at least two coupling means for establishing said gear trains, and means for controlling the operation of the coupling means. said controlling means including an accelerator for controlling the power impressed on said input member. means under the control of said accelerator for simultaneously conditioning the coupling means to effect an upward change in speed or the output member when said accelerator is moved to its minimum power setting and means under the control of said accelerator for conditioning the coupling means individually to effect diiferent downward changes in speed of said output member when said accelerator is moved to its maximum power setting.

8. A variable speed ratio power transmittin device comprising input and output members. a plurality of gear trains for driving the output member from the input member. said gear trains including low, second. third and fourth speed ratios, at least two coupling means for establishing said gear trains, and means subiect to the inlicence of the speed of the output member and controlling the operation of the coupling means. an accelerator for controlling the power imp on said input member said controlling means being under the control of said accelerator and being adapted to effect an upehii't from low to rourth speed directly on an operative stroke or the accelerator. and means under the control of the accelerator and subject to the influence of the speed of the output member for effecting shifts individually from fourth speed to third speed and from fourth speed to second speed on operative strokes of the accelerator.

4. A variable speed ratio power transmittin device comprising input and output members, a plurality of gear trains for driving the output member from the input member. at least two coupling means for establishing said gear trains, electromagnetic means for controlling the operation of the coupling means. means subject to the influence of the speed of one of the members and adapted to cause the electromagnetic means to operate said two coupling means simultaneously, and a circuit including additional means controlled by the speed of the output member and a plurality or manually controlled switches for individually operating said electromagnetic means in a reverse sense.

5. A variable speed ratio power transmitting device comprising input and output members, a plurality of gear trains for driving the outpui member from the input member, at least two coupling means for establishing said gear trains, and electromagnetic means {or conditioning the coupling means for operation, said electromagnetli means comprising a solenoid for each couplin means. a relay for each solenoid. a relay controlling both solenoid relays, and speedresponsivi means controlling the last-mentioned relay whereby both coupling means may be operated simultaneously when a predetermined speed i reached.

6. A variable speed ratio power transmittim device as described in claim 5, and manually op erable means and a switch operated by one of sail coupling means. for overruling the speed respon sive means as to one of the solenoid relays, where by to operate only one of the coupling means t effect a downward change in speed.

7. A variable speed ratio power transmittin device as described in claim 5, and means for over ruling the speed responsive means including manually operable switch, a couplinl p rate switch, and a second speed responsive switc' whereby one of the coupling means may be oper ated to eifect a downward change of speed withi a predetermined range of speeds only.

8. A variable speed ratio power transmittin 7s device as described in claim 5, and means operabl within one range of speeds for overruling the speed responsive means and effecting an operation one of the coupling means to produce a downward change in speed, and operable within another range of speeds, for overruling the speed responsive means and eilecting an operation of the other coupling means to produce another downward change in speed.

9. A variable speed ratio power transmitting device comprising input and output members, a plurality oi gear trains for driving the output member from the input member including low-. second, third and direct drive, at least two couplings for establishing said gear trains, electromagnetic means for conditioning the coupling means for operation, said electromagnetic means comprising a solenoid for each coupling means, a relay for each solenoid, a relay controlling both solenoid relays, and a switch controlled by the speed of the output member for controlling the last-mentioned relay whereby both couplings ma be operated simultaneously to produce a direct drive when a predetermined speed is reached.

10. A variable speed ratio power transmitting device comprising input and output members, a plurality of gear trains for driving the output member from the input member including low, second, third and direct drives, at least two coupling means for establishing said gear trains, electromagnetic means for conditioning the coupling means for operation, said electromagnetic means including a solenoid for each coupling means, a relay for each solenoid, a relay for controlling both solenoid relays, a switch operated in response to the speed of the output member for controlling the last-mentioned relay whereby both couplings may be operated simultaneously to produce a direct drive from low when a predetermined speed of the output member is reached, a foot pedal operated throttle control member having maximum and minimum power positions, and a switch operated by the pedal at its maximum power operating position for eiiecting a downshift from direct drive to third speed, thereby overruling the governor.

11. A variable speed ratio power transmitting device comprising input and output members, a plurality of gear trains for driving the output member from the input member at low, second, third and direct drives, at least two coupling means for establishing said gear trains, a foot-operated pedal for controlling the power impressed upon the input member, said pedal being movable from a minimum power setting to a maximum power setting, electromagnetic means for conditioning the coupling means for operation, said electromagnetic means including a solenoid for each coupling means, a relay for each solenoid, a relay controlling both solenoid relays, a, switch controlled by the pedal at its maximum power setting and a switch controlled by the speed of the output member for controlling the last-mentioned relay, whereby both couplings may be simultaneously operated when a predetermined speed of the output member is reached to effect a shift from low to direct drive, and a second speed responsive switch controlled by different speed ranges of the output member, said pedal-operated switch and the second speed responsive switch together being adapted in one speed range of the output shaft to effect a shift from direct drive to third speed and in another speed range to eflect a shift from direct drive to second speed, when the pedal-controlled switch is moved to its maximum power setting.

12. A variable speed ratio power transmittin! device as described in claim 11, the shift from direct drive to third speed being eflective only in one predetermined range of speeds of the output member and the shift from direct drive to second speed being effective in a lower range of speeds of the output member.

13. A variable speed ratio power transmitting device as described in claim 11, and means for interrupting the ignition when a downshift is to be eflected from direct drive to third speed and from a direct drive to second speed.

1 4. A variable speed ratio power transmitting d v e comprising input and output members, a plurality of gear trains for driving the output member from the input memben-at least two coupling means for establishing said gear trains, power means for controlling the operation of the coupling means, an accelerator for controlling the power impressed on said input member, means subject to the influence oi the speed of one of the members and under the control of said accelerator and adapted to cause the power means to operate said two coupling means simultaneously when said accelerator is moved to its minimum power setting, and a power circuit including an additional means controlled by the speed or the output member and a plurality or manually operated devices under the control of said accelerator for individually operating said power means in a reverse sense when the accelerator is moved to its maximum power setting.

15. In a transmission system, in combination, an input member; means for supplying torque to said input member and including an electrical ignition system; an output member; coupling means for establishing a driving relationship between said members; means for shifting said coupling means to disestablish said driving relationship: means, including means responsive to a predetermined speed of the output member for conditioning said shifting means to shift said coupling means to disestablish said driving relationship when the speed of the output member is below said predetermined speed; an accelerator for re ulating the torque supplied to the input member by said torque supplying means; and means rendered effective by movement of said accelerator to its released position to interrupt said ignition system, when the output member is moving below said predetermined speed, to cause operation of said shifting means to disestablish said driving relationship.

16. In a transmission system, in combination, an input member; an engine for supplying torque to said input member and including an electrical ignition system; an output member; coupling means for establishing a driving relationship between said members; means for shifting said coupling means to disestablish said driving relationship; means, including means responsive to a predetermined speed of the output member, for conditioning said shifting means to shift said coupling 'means to disestablish said driving relationship when the speed of the output member is below said predetermined speed; an accelerator for regulating the torque supplied to the input member by said engine; and means, including a switch closed by movement or said accelerator to its released postion, to interrupt said ignition system, when the output member is moving below said predetermined speed, to cause operation of said shifting means to disestablish said driving relationship.

17. In a transmission system, in combination, an input member; an engine for supplying torque to said input member and including an electrical ignition system: an output member; coupling means for establishing a driving relationship between said members: electrical control means responsive to a predetermined speed of the output member; means for shifting said coupling means to disestablish said driving relationship; electromagnetic means. rendered eflective by said lastnamed means when the output member is moving below a predetermined speed. for conditioning said shifting means to shift said coupling means to disestablish said driving relationship; an accelerator for regulating the torque supplied to the input member by said engine; and means. including a switch closed by movement oi said accelerator to its released position. to interrupt said ignition system, when the output member is moving below said predetermined speed, to cause a fluctuation in the torque supplied by the engine in order to cause operation 01 said shitting means to disestablish said driving relationship.

' JOHN B. POLOMBKI.

UNITED STATES PATENTS Number Name Date 1,985,994 Banker Jan. 1, 1935 2,012,296 Banker Aug. 21. 1935 2,151,714 Pavesi Mar. 23, 1939 2,225,493 Barnes Dec. 17, 1940 2,237.29! Banker Apr. 9, 1941 2,257,674 Dunn Sept. 30, 1941 2,257,833 Claytor Oct. '7. 1941 2,304,863 Thompson Dec. 15, 1942 2,328,291 Osborne Aug. 31, 1943 2,333,668 Neraeher et al Nov. 9, 1943 2,339,473 Griswold et a1. Jan. 19, 1944 2,342,960 Neraeher et a1 Feb. 29, 1944 2,343,312 Maui-er liar. 'l. 1944 

